In any surgical procedure involving entry into any body cavity, such as puncture of the eyeball or the abdomen, it is of the utmost importance that the surgeon know precisely where his surgical instrument is with respect to the wall of the body cavity. Under conventional procedures, for example, however, the surgeon must proceed blindly during a puncture of the abdominal wall, at least until a pneumoperitoneum has been formed.
For example, in surgical operations involving the puncture of the abdominal wall the surgeon must know immediately when the puncturing instrument, such as a trocar or needle, has entered the abdominal cavity. The peril of puncturing the intestines, or even the aorta, arises as soon as the puncturing instrument enters the abdominal cavity.
To try to mimimize these dangers, instruments and procedures have been developed for giving a signal to the surgeon when the wall of the body cavity has been pierced. One such well-known instrument is the Verres needle. This instrument comprises a needle-like trocar, including a sharpened outside cylinder, and a tubular sensor positioned inside the trocar. The distal end of the sensor normally extends beyond the sharpened point and is spring-biased into this position.
When the Verres needle is being used to puncture the ab- of the body cavity, such as the abdominal wall, the distal end of the senor is pressed back into the trocar by contact with the outer surface of the wall. As soon a the needle-like trocar pierces the wall, however, the sensor is driven outwardly into the cavity by the spring bias. The movement of the sensor signals the surgeon that a puncture has been completed, but the surgeon is completely blind as to the conditions which the piercing instrument and the sensor have encountered.
The distal end of the sensor of the Verres needle is closed by a substantially hemispherical surface. Adjacent this hemispheric closure is an opening for the emission of gas. It is conventional procedure in the puncture of the abdominal wall, after the puncture to allow gas such as carbon dioxide or niturous oxide, under pressure, to flow into the abdomen to lift the abdominal wall away from contents of the abdomen to form a pneumoperitoneum. The danger of inadvertent puncture of an organ in the abdomen is thus reduced.
Perils, however, accompany the use of the Verres needle, which is blind. The abdominal wall, for example, itself is often separated into two wall portions with a cavity therebetween in a condition called preperitoneal emphysema. In this condition, which may not be foreseeable by the surgeon, the distal end of the sensor of the Verres needle enters the preperitoneal cavity and the emitted gas expands the cavity between the inner and outer portions of the abdominal wall. The surgeon then prepares for further procedures, even though the abdominal cavity, itself, has not been entered, unknown to the surgeon.
After the gas has been emitted through the Verres needle, the needle is removed the puncture enlarged by small incisions, and another instrument inserted. The second instrument customarily is a larger solid body trocar for enlarging the puncture made by the Verres needle. Such a solid body trocar includes a solid cylindrical body slidably mounted in a sleeve. The solid cylindrical body has a sharpened point formed by three or four cutaway portions forming a pyramidal point.
The solid body trocar has a relatively large diameter but varying in diameter in accordance with the procedure. This instrument is inserted into the puncture made by the Verres needle blindly by the surgeon. The danger of puncturing an organ in the abdomen, for example, by the large solid body trocar is severe and such a puncture is not always apparent. Of course, if the aorta is punctured, the patient dies quickly.
After the diameter of the puncture has been enlarged by the solid body trocar, including the sleeve, the solid portion of the trocar is removed and an endoscope is inserted through the sleeve to inform the surgeon visually as to the conditions under which further procedures may be advanced.
Under conventional procedures, therefore, the surgeon not only must puncture the body wall blindly, but must first insert the Verres needle, remove the Verres needle, insert the solid body trocar, remove the trocar, and then through the trocar sleeve, insert an endoscope, which conventionally may include an operating channel. It is to be understood that the term "endoscope" is used broadly herein and inludes laparoscopes, peritoneoscopes, and other types of specialized endoscopes.